Apparatus for contour rolling



June 5, 1956 R. P. KOEHRING ET Ax. 2,748,534

APPARATUS FOR CONTOUR ROLLING A Filed April 10, 1952 3 Sheets-sheet 1INI/ENTORS` [ar] E IA/JY'EHS 3 WM June 5, 1956 R. P. KOEHRING ET AL2,748,634

APPARATUS FOR CONTOUR ROLLING 5 Sheets-Sheet 2 Filed April lO, 1952 fINVENToRs f x 54 C7 4 1Y0/5nd E KBJ'Jhq [far] E. MXENS 32 WM W June 5,1956 R. P. KOEHRING ET Ax. 2,748,534

APPARATUS RoR coNTouR ROLLING 5 Sheets-Sheet 5 Filed April lO, 1952 yINVENTORS Edf] E', MMT/75 fafa/7a ffice/711mg United States Patent OAPPARATUS FOR CONTOUR ROLLING Roland P. Koehring and Carl E. Wilkens,Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., acorporation of Delaware Application April 10, 1952, Serial No. 281,554

1 Claim. (Cl. 80-23) i This invention relates to an apparatus forcontour rolling articles made from sintered metal powders.

It is, therefore, the basic object of the invention to provide anapparatus for shaping, while cold, articles from sintered metal powderswhich are molded and sintered to the approximate shape desired and arethen contour rolled to the exact shape desired.

Another object of the invention is to provide an apparatus for contourrolling articles made from the sintered metal powders wherein therolling operation accomplishes two major results, namely, the propershaping of the article and an increase in the physical properties, suchas, density, tensile strength, etc., of the article either over itsentire extent or at predetermined and selected portions thereof.

In carrying out the above object, another object of the invention is toprovide apparatus for contour rolling projectiles comprising threecontouring rolls wherein one of said rolls utilized includes an endiiange predetermining the length of the projectile and wherein back-upro-lls are provided for each contouring roll, which back-up rolls aresuitably recessed for clearance purposes adjacent portions of thecontour rolls which are not subjected to maximum stress.

A still further object of the inventio-n is to provide an apparatus forcontour rolling articles and similar objects wherein three contour rollsare utilized together with three back-up rolls therefor and wherein oneof the contour rolls is driven, which driving force is transmitted tothe other rolls through suitable gearing so that all rolls arepositively rotated at the same speed.

Another object of the invention is to provide an apparatus whereingearing is provided for associating the various contour rolls andwherein the one roll is adjustably mounted for vertical displacement andisv hingedly connected to the driving gear so as to always be held insimilar relation to said gear regardless of displacement of the roll.

it is still a further object of the invention to provide an apparatusfor contour rolling articles made from sintered metal powders wherein apair of rolls relatively movable with respect to each other areprovided, which rolls have the desired contour of the part to be formedon the surfaces thereof, a third member being provided to position thepart between the'` contour rolls during the rolling operation.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein preferred embodiments o-f the present invention areclearly shown.

In the drawings:

Fig. 1 is an end view of a contour rolling apparatus.

Fig. 2 is a sectional view taken on line 2-2 of Fig. l.

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a diagrammatic end view showingv one contour roll in displacedposition.

Fig. 5 is a diagrammatic end view of the apparatus shown in Fig. 4,wherein the displaced roll is in contouring position.

v 2,148,634 Patented June 5 1956 Fig. 6 is a side view of anotherembodiment of the apparatus used for contouring.

Fig. 7 is a view taken on line 7--7 of Fig. 6.

Fig. 8 is a diagrammatic view of the contouring rolls shown in Fig. 7,showing the relative position of the rolls, pushing member and part tobe contoured.

ln the manufacture of cylindrical articles from sintered metal powder;for example, in the manufacture of projectiles and the like, it is quiteditiicult to briquet the metal powder prior to sintering in the exactshape designed, whereby, when the article is sintered, additionalmachining operations are normally required to bring the article to theexact shape and size desired.

Then too, in cylindrical articles of this type, it is very ditiicult tosize thearticle after sintering by the usual methods used in powdermetallurgy, for example, by pressing through a button die or the like.

Furthermore, it is often very desirable to markedly increase the densityor other physical properties, such as, tensile strength, after thesintering operation. This can be accomplished by suitable pressing ofthe article which, due to its porosity, can be changed in over-alldimensions slightly to provide for an increase in density and alsoprovide increase in tensile strength. Then too, in an article, such as aprojectile, it is often very desirable to have one portion of higherdensity than another, for example, the driving band should be relativelysoft whereas the body of the projectile is preferably rather hard anddense so as to prevent distortion due to tiring. Also, it is oftendesirable to have a relatively soft nose portion so that the projectilewill shatter or mushroom, etc., as desired. Thus it is apparent thatvarying density throughout a projectile is an optimum condition which isquite impossible to obtain on cast objects and which, prior to ourinvention, was diicult if not impossible to obtain on cylindricalarticles made from sintered metal powders.

We have found that contour rolling of sintered metal powders in the formof projectiles, etc., can vary well be carried out to not only size thearticle to the exact size desired and to shape the article at certainportions thereof and in addition, we have found that it is possible toselectively regulate or control the density of predetermined portions ofthe article during the sizing operation. In this instance, the sizing iscarried out by contour rolling since the article is generallycylindrical in shape.

Contour rolling of such an article may be accomplished on apparatus asshown in the accompanying drawings. This apparatus 2G includes threecontour rolls 22, 24 and 26 positioned at 120 apart. Each roll isjournaled at both ends in end plates 28 and 3i) which are carried by abase plate 32 of the apparatus. The uppermost roll 22 is journaled on aslidable plunger member 34 which is movable vertically so that the roll22 may be moved toward or away from rolls 24 and 26. On the uppermostend of the plunger 34 is a platform 36 whereby the roll 22 may be forceddownwardly through a press member, not shown, acting against theplatform 36. In other words, the entire apparatus 2i) may be positionedin a press with the base plate 32 against the lower platten and theplatform 36 against the upper platten. The part to be contour rolled isa projectile 38, and as the press forces the. contour roll 22downwardly, the article 38 is sized between the three rolls 22, 24 and26. It will be noted that each of the rolls 22, 24 and 26 is backed upby backup rolls designated at 40, 42 and 44. These backup rolls are alsojournaled on side plates 28 and 30 and are in contact over the majorportion of the surfaces of the contour rolls 22, 24 and 26 respectively.The backup rolls are merely idler rolls which turn with the contourrolls. The contour rolls, however, are driven by a suitable mechanismsuch as a motor through a gear reducer attached to the shaft 46. Shaft46 is in direct connection with roll 24 which has a gear 4S thereon thatmeshes with a large idler gear 50. The idler gear 50 meshes with gear 52attached to roll 22. Gear 43 also meshes with a second idler 54 whichengages a gear 56 associated with the contour roll 26. Thus the contourroll 24 is directly driven by the prime mover and, through idlers 50 and54, directly drives contour rolls 22 and 26, respectively.

Roll 24 is attached by a hinged member 58 to the idler gear t) whichdefinitely controls the distance between the gears so that they arealways in mesh. Similarly, gear 52 is carried by a hinged member 60 alsoattached to the Shaft of idler gear 50. ln this manner, as the roll 22is raised vertically by the plunger 34, the gear 52 rides around thesurface of gear 50 and remains in engagement therewith regardless of thevertical position thereof, Similarly, the gear 50 rides around gear 4Sassociated with roll 24, as noted in Fig. 4. The relation of immovablegear 48 to the idler 54 is constant whereby the gear 56 and itsassociated roll 26, which are also immovable, are constantly driven.Thus the hinge mechanisms 58 and 60 permit movement of the contour rolls22 and 24 and their associated gears 48 and 52 while at no timepermitting the gears to become unmeshed with the idlers 50 and 54 sothat all of the rolls are positively driven in all positions of theapparatus.

The diagrammatic View in Figs. 4 and S wherein the hinged members 58 and60 have been reduced in thickness, clearly show the adjustability ofposition of the gears while said gears remain in mesh.

Fig. 3, which is a cross sectional view through the apparatus, showsquite clearly how the article 38 is contour rolled between the threecontour rolls together with the action of the backup rolls thereon.After the pressure is applied to the upper plate 36, the contour rolls,due to the compressibility of the porous metal article, move toward acommon center on their 120 spaced axes and gradually roll into thearticle 38 the desired accurate contour while simultaneously increasingthe density and tensile strength thereof.

The use of the backup rolls 40, 42 and 44 is quite necessary to thesuccess of the invention. The contour rolls 22, 24 and 26 mustnecessarily be of rather small diameter which is more or less regulatedby the diameter of the article to be rolled. In the instant case, thecontour rolls have ridges at 62 which bite into the article, such as aprojectile, and hold the article spaced in a horizontal position. Thelarger diameter end flanges 64 likewise aid in this positioning. Thedrive band on the article is noted at 66 and is not appreciablycompressed due t0 the fact that the grooves 68 are provided in thecontour rolls. Thus, the projectile is provided with an integral drivingband that is relatively soft and of lower density than the remainder ofthe article. At the forward end of the contour rolls, the nose portionof the projectile is shaped and it will be noted that one roll, namely,roll 22, has a large diameter flange 70 thereon which slightly overlapsthe ends of rolls 24 and 26. This definitely sets the length of theprojectile and likewise prevents the projectile from sliding forwardwithin the rolls and thereby getting out of position. The roll 22 isbacked by roll 40 and by a large flange 72 on the roll 40. As thepressure is placed on the projectile, the main body portion of theprojectile is formed by the major portion of the rolls which are backedup by backup rolls while the nose portion is formed between the threerolls and is definitely Set for length by the flange 70. Outwardmovement of the roll 22 is prevented by flange 72 on backup roll 40rotating in groove 73. It will also be noted that all of the backuprolls have a groove 74 therein which registers with the flange 64 on thecontour rolls and further prevents outward or radial movement of saidrolls. Similarly, the backup rolls are relieved at 76 since the changingdiameters would be difficult to back up and cause excessive friction asthe rolls are moved.

The entire apparatus therefore -is one to provide pressure rolling on acompressible material wherein the contour rolls are positively drivenfor positively rotating the article to be contoured and wherein thecontour rolls are positively backed up to pevent distortion or bowingthereof and are positively held against radial movement through flangeson the backup rolls. When the article has been properly contoured asdetermined by the extent of downward movement of the plunger member 34,member 34 is backed off the finished article 38, removed from theapparatus and another article is pressed therein for contouring.

A modification of the apparatus, as shown in Figs. l through 5,inclusive, is depicted in Figs. 6 through 8. 'Ihis modificationeliminates the necessity of backup rolls as used in the apparatus shownin Fig. l, for example. When using three rolls, it is apparent that thediameter of the rolls limits the size of the article which may be rolledtherebetween and therefore in order to roll a rather small diameterarticle, such as shown at 38 in Fig. 2, it is necessary to use smalldiameter rolls which do not have sufficient strength to prevent bowing.In order to strengthen such rolls, heavy backup rolls are necessary. Inthe embodiment of the apparatus, shown in Fig. 6, the necessity ofbackup rolls is eliminated through the use of two rotatable memberswhich may be of any necessary size to yield the desired strength. Thetwo rolls cooperate with a pushing member to center the part beingcontoured therebetween.

Referring specifically to Fig. 6, a frame member 71 is provided on whichis journaled a stationary roll 73 and a movable roll which is carried ona frame member 77 slidable in tracks, not shown, in the member 7l. Themember 77 is spring biased to cause rolls 75 to be spaced from rolls 73except when pressure is supplied to the frame 77. For example, theentire apparatus may be placed in a punch press or other suitablemechanism to cause the frame 77 and its associated roll 75 to movetoward the roll 73 in the frame 71.

In practice, stops are provided in the tracks so that the downwardtravel of the frame 77 may be adjustably limited. Each of the rolls 73and 75 are driven by chains 80 and 82 which engage sprockets 84 and 86,respectively, carried by the shafts of the rolls 73 and 75. The otherend of the chains 80 and 82 engage sprockets 88 and 90, not shown, whichsprockets are driven by a suitable power mechanism, for example, a speedreducer driven by a motor, not shown. Thus the chains 80 and 82, throughtheir associated sprockets and motor, cause the rolls 73 and 75 torotate at a desired speed in the direction shown in Fig. 8 by the arrowson the rolls. The surfaces of the rolls 73 and 75 are contoured at 92and 94 as noted in Fig. 7, so that an article, such as a projeetile, maybe rolled therebetween to the desired size and contour, as previouslydiscussed in connection with the apparatus shown in Fig. 1.

In order to hold the projectile or other object between the rolls 73 and75, a. pusher 96, which is adjustable to or away from the common centerof the rolls is provided. The pusher 96 has a hardened contact member 98thereon which engages the part to be contoured. In this instance, it ispreferable to have the part to be contoured so positioned between therolls that the center of the part is approximately .001 to .003displaced from the common center of the rolls toward the pusher 96.Thus, the pusher 96 maintains the part to be rolled between the rollswhere it rotates as the rolls rotate. During the contouring operation,the frame 77 is pressed downwardly against its resilient mounting untilthe full and final contour is obtained on the part.

The pusher 96 is adjustably mounted on the frame 71 and may be movedinwardly or outwardly by means of a screw handle 100. Once thisadjustment is properly made, it is usually unnecessary to further adjustthe pusher since the travel of the frame 77 may be adjusted to cause thepart 38 to assume the desired diameter during contouring.

If desired, it is also possible to cause the pusher to be operatedthrough a rack and pinion, not shown, so as to move inwardly at the samerate of travel as the rolls 73 and 75 move toward one another. In thisinstance, the part 38 is maintained in substantially identical relationto the three parts of the contouring machine, namely, rolls 73 and 75and pusher 96. In all cases, the pusher is mounted on the frame 71 withits contact member 98 engaging the part to be rolled as noted.

The contact member 98 is relatively small compared to the part 38 beingcontoured and presents very little friction so that no substantialgalling action is apparent. The rubbing surface of member 98 may beslightly rounded to present a line Contact for reducing a friction. lnsome cases, it may be desirable to replace the member 98, as shown, witha roller member to further reduce friction, although we have found thata hardened bar yields very satisfactory results. In either case thecontact member 98 may be contoured if it contacts contoured portions ofthe part, although it is preferred to use a member 98 which includes astraight edge only for bearing against uncontoured portions only of thearticle 38. This may be accomplished since the extent of the member 98is not critical, merely being used to maintain the part in position.

It will be noted that in both embodiments of the invention a pair ofcontour rolls are utilized which compress and contour the part to beshaped, while the part is being rotated therebetween. ln each instance,a third member holds the part in proper relative position with respectto the contouring rolls and in this manner, it will be apparent thatboth forms of the invention utilize similar functions to perform thecontouring operation.

While the embodiments of the present invention as herein disclosed,constitute preferred forms, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

Apparatus for contour rolling cold porous metal articles of theapproximate size and shape to the exact size and shape desired,comprising in combination; three rotatable contour rolls, two of saidrolls being permanently mounted against any displacement and a thirdroll mounted for vertical displacement with respect to the other tworolls, gearing associating all three rolls for concomitant rotation,said gearing including a pair of gears movable during verticaldisplacement of said third roll for keeping all three rolls in gearedrelation at all times, three backup rolls, one being provided for eachof said contour rolls and disposed on a line drawn through the axis ofeach of said contour rolls and the axis of the part to be contoured, aflange at one end of the displaceable roll adapted to continuouslyengage an abutting flange on the backup roll therefor for preventinglateral displacement of said displaceable roll, a second ange on theopposite end of said displaceable contour roll continuously engaging thegroove in the backup roll therefor for aiding in preventing lateraldisplacement thereof and flanges in each of said permanently mountedcontour rolls continuously riding in grooves in their respective backuprolls whereby the contour rolls are held against lateral displacementand in proper vertical alignment at all times.

References Cited in the le of this patent UNITED STATES PATENTS 672,516Schinneller Apr. 23, 1901 1,015,412 Werckmeister Ian. 23, 1912 1,370,998Roemer Mar. 8, 1921 1,493,836 Wurster May 13, 1924 2,139,872 WorthingtonDec. 13, 1938 2,318,505 Long May 4, 1943 FOREIGN PATENTS 302,513 GermanyIuly 22, 1919

